In automated poultry processing facilities, the birds are feed through a series of processing stations wherein they are killed, defeathered, eviscerated, and subsequently cut up into component parts for packaging and shipment to market. In the cut up operations of the poultry carcasses, it is a common practice to cut the feet from the legs and then to cut the connected leg and thigh segments from the carcass at the torso. The separated leg and thigh segments can then be cut to produce individual leg and thigh parts, which can be packaged separately, or the meat can be removed from the bones of the leg and thigh for commercial use in preparing soups, meat pies, frozen dinners, and the like. This process of removing the meat from the bones is commonly referred to as a "deboning" process.
In the past, several methods have been developed to debone the legs and thighs of poultry, which methods generally employ some type of scraping tool that engages the bone of a leg or thigh and scrapes along its length. For example, U.S. Pat. No. 4,811,456 discloses a pair of notched scraping blades that closely straddle a bone of the poultry part, such as a thigh, and are moved longitudinally along the length of the bone to progressively scrape the meat from the bone. U.S. Pat. No. 4,488,332 discloses a deboning apparatus comprising a resilient flexible stripping device having a hole therein through which the bone is thrust to pry the meat from the bone. While both of these methods work satisfactorily in deboning a single bone segment, they nevertheless have difficulty in deboning a multi-segmented poultry part, such as a connected leg and thigh.
Consequently, poultry deboning machinery has been developed for deboning connected leg and thigh segments of poultry. For example, U.S. Pat. No. 2,897,536 discloses a poultry deboning machine comprising a pair of opposed rotating meat stripping rolls adapted to strip or pull the meat from the bones from a connected leg and thigh segment as the leg and thigh segment is pulled between the inner section of the two rotating rolls. U.S. Pat. No. 3,261,054 discloses a leg deboning machine comprising a pair of opposed stripper bars that engage the bones of a leg and thigh segment and scrape along the entire length of the connected leg and thigh as the poultry part is pulled past the stripper bars.
What the two foregoing machines, as well as other machines, have in common is that they debone a leg and thigh part by moving a stripper mechanism from one end of the leg and thigh segment to the other. A common problem encountered by attempting to remove the meat from connected leg and thigh segments by this method is that it is difficult to maneuver the stripping mechanism around the enlarged joint connecting the bones. Either the pressure exerted by the stripper mechanism is insufficient to remove all of the meat from the bones, or the pressure is so great that undesirable pieces, such as cartilage, tendons, and ligaments, are removed along with the meat, or the joint is broken by the force and the leg bone is pulled from the thigh bone along with the meat.
In addition, the commercial valve of the meat is enhanced if it can be removed in one large piece with the skin in tact. Such a cut is known as a "Japanese cut", and it is desirable for preparing certain specialty dishes, wherein vegetables are stuffed in the meat and the skin is enveloped around the vegetables for cooking. However, due to the difficulty in maneuvering the stripping device around the enlarged joint without stripping cartilage from the joint, the meat is often separated in several pieces or the skin is ripped or torn.
Moreover, many automated deboning machines require that once the meat is pulled from the bones, that it be cut to separate is completely from the bone. To accomplish this, a cutting device typically is placed adjacent the bone in a position to engage the meat and cut it from the bone after the meat is pulled off of the bone. However, such an automated cutting step often results in undesirable cartilage or tendons getting cut along with the meat.
Accordingly a heretofore unaddressed need exists for an improved method and apparatus for deboning the legs and thighs of poultry to produce a single chunk of meat relatively free of undesirable cartilage or bone fragments with the skin in tact around the meat.